On a quad core cpu, does each core have its own ax register?

[georgelappies]

Or is there only one ax register shared between the 4 cores?

[Frank Kotler]

I'm not very familiar with multi-core CPUs, but I think the question may be meaningless. I don't think you'll be switching CPUs without switching execution threads. Essentially, each core does have its own ax register, but it is saved and restored when tasks are switched, so you'll always have "your own" ax register to work with. I don't think it's anything you need to worry about, unless you're writing your own multi-tasking OS.

I think that the "true" answer is more complicated than that, but I hope that'll suffice. Corrections welcomed!

Best,
Frank

[Cyrill Gorcunov]

yup, each core has own registers set, they are not shared.

[Cyrill Gorcunov]

(fwiw, except of some msr registers, you need intel/amd manual for details)